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Many autos are actually based on manual calibers that have heavily modified bridges to accommodate the requirements of a bolt on auto module. If you look closely at some of the AS manual winders for instance you will notice that there are a lot of odd holes in the main plates and even in some of the bridges that don't seem to serve any purpose. Some of these are to make the main plate common to both calendar and non-calendar variants, and I would be surprised if some of them weren't for auto module functions. In fact if you look at Ranfft you will see in a number of database entries the whole movement family is listed, usually starting with the base manual movement, and progressing with the addition of complications.
I might therefore be possible to start with a manual winder that is part of a whole family of movements which includes autos and swap out all of the different parts to make it an auto, but the cost would be out of all proportion to simply buying the auto movement in the first place, and then it would be unlikely to fit in the case that the original manual winder came from, requiring a new case to be sourced as well. So theoretically possible, but why would you do that?
Converting a manual caliber that has no auto DNA included as standard is also feasible. I recall reading about one maker that has managed to add auto winding to the venerable Unitas/ETA 6497, a classic manual winder, although I can't remember who it was. In fact a lot of the early autos were just that, but it's only possible if you have the design and manufacturing capability to devise and make the relevant parts.

Isn't the impulse jewel common to both movements?
Since the "C" has a jewelled barrel arbor hole which isn't jewelled on the "B", in order for the jewel count to be correct for both movements the "B" must have a jewelled bearing that is not jewelled on the "C".
It would be interesting to see what aspect of the "C" was improved by removing a jewel, even if it just turns out to be the cost of manufacture.

Awww. Mine are definitely much better JDR. . To be honest I don’t know, but that’s certainly an enviable display of screwdrivers. The grips aside, the main improvement I found was the precision ground stainless steel blade. Nice display box! Sent from my iPhone using Tapatalk

Isopropanol will soften and wash away the shellac. Take care with the balance and pallet fork. Just a quick dip of a few seconds, then straight onto watch paper to take off the excess, then use a puffer to dry the critical areas where the shellac bonds on the jewels. After 4 years using lighter fluid and thinking I was getting parts clean, I now use Elma watch cleaning product. Amazing how I fooled myself about how clean was clean. Also, try an ultrasonic which are very cheap nowadays. In general, IPA (isopropyl alcohol)is not a good cleaner, but is good for the final fine rinse if done quickly. Sent from my iPhone using Tapatalk